DHCP Lease Duration Tips

A DHCP lease is the time period a DHCP server assigns an IP address to a client. The default DHCP lease time for DHCP scopes is 8 days.

Tip#1 increase lease time for fixed devices

For small networks, you can leave the lease time to the default setting of 8 hours.

For large networks, consider changing the DHCP scopes for fixed devices (workstations) to 16 days. This can reduce DHCP related network traffic. Workstations don’t move very often so they don’t need to go through the whole DHCP dance as often to obtain an IP address.

Tip#2 reduce the lease time for guest/mobile devices

If you provide guest wifi these DHCP scopes can become exhausted of available IPs very quickly. These devices most likely just need temporary access such as a few hours. For these scopes consider adjusting the DHCP lease time to 1 hour. If the device is still active it will renew but if the device disconnected it will free up an IP address. This should help with available IPs on your guest scopes.

This can also be the case with mobile devices, this one can be tricky though with more and more users having laptops. The default of 8 days may be sufficient but if you know of mobile devices that move around a lot you may consider reducing the lease time.

Summary
If you have DHCP scopes that serve specific devices such as workstations only then consider adjusting the DHCP lease times.